Supermarket Sainsbury’s has kicked off April Fools’ Day with the announcement that it is to introduce bread which always falls butter-side up.

On its website, Sainsbury’s claims: “Our butter-side-up bread is baked in higher temperatures allowing for a more rapid expansion of the dough. This process helps create larger air pockets in the loaf, which in turn absorbs your butter and jam more evenly. This absorption helps distribute the weight of your condiments in a balanced way and negate any disproportionate weight bias. It also reduces the uneven drag in mid flight.

“Our innovative new bread slicing method leaves our loaves with an ever-so-slight curvature, almost unidentifiable to the naked eye. This curve adds a greater weight to the unbuttered side of your toast resulting in a butter-side-up reaction 99% of the time.”